A recent medical study showed that more than 50% of throwing shoulders in young baseball players without shoulder pain had MRI abnormalities

These MRI issues have the potential to cause long term issues for the shoulder

Players who played more than 8 months out of the year and were baseball-only athletes had a 100% chance of an abnormal MRI, regardless of playing position

At least once a week I’ll see a young athlete in the clinic with shoulder pain and at the end of a careful discussion, physical exam, and further discussion with the parents I’ll hear “that’s great, now can he have his MRI this afternoon”. The desire for an MRI is normal and natural on the part of the parents, after all this is what the media tells us will happen in a professional athlete.

(And btw the truth of that interaction with a pro athlete is frequently very different than what’s reported). But this study, published about a month ago in the Orthopaedic Journal of Sports Medicine provides valuable insight. An alarmingly high number of non-painful throwing shoulders in young athletes will have MRI abnormalities compared to the athlete’s own non-throwing shoulder.

The shoulder is frequently injured in young baseball players. Sports medicine doctors will often treat these athletes for overuse injuries and structural problems. Many of these diagnoses have long-term implications, sometimes requiring surgery and putting young athletes at risk for future problems. You’d be far better off not having any of these conditions.

Author Andrew Pennock and colleagues from UC San Diego orthopaedic surgery performed the study. They performed MRI evaluations on 23 young male baseball players aged 10-12 with no reported shoulder issues, and did MRI scans on the throwing and non-throwing shoulder.

Here were some of their key findings from the MRI portion of the study:

52% of the throwing shoulders had MRI abnormalities that were not present in the non-throwing shoulder

They identified 2 key risk factors: year round play (defined as 8 or more months of baseball play per year) and single sport specialization

If a player had 1 of the 2 risk factors there was a 71% chance of an abnormal MRI; and with 2 of 2 risk factors there was a 100% chance of an abnormal MRI

Player position did NOT correlate with an abnormal MRI, meaning that fielders could also have an abnormal MRI

There were also some interesting observations about player behavior and knowledge of rules and recommendations for shoulder safety. 83% of the players were aware of pitch count restrictions, innings restrictions, and PitchSmart recommendations, and yet it appears that the number of players who actually followed the recommendations was small. In this study, 43% played baseball more than 8 months per year, 22% were single-sport athletes, and 80% of pitchers threw curveballs, sliders, and sinkers.

There are some limitations to this study that require additional investigation. It’s a fairly small number of players, and we don’t actually know what happens down the line to the shoulders with abnormal MRI scans.

If you’re parents or coaches of young baseball players please have a look at the guidelines and rules in place from Little League Baseball and PitchSmart, and then make a commitment to actually follow the rules. A healthy arm is much better for long-term health and near term performance.